Standardization of high harmonic components and their suppression features in mixed overhead and cable dc line

In the article the standardization of the disturbing interference of DC line harmonic currents is considered. The effectiveness of the methods of higher harmonic component suppression for mixed direct current transmission media consisting of overhead line and cable is analyzed on the example of LAES-2-Viborgskaya station HVDC transmission system. It is shown, that increasing of the smoothing reactor inductance isn´t an efficient measure to reduce harmonic components levels, especially when quite strict ratings for telephone interference are established. Scheme of passive double frequency filter is offered and its parameters are calculated; such filter enables to considerable reduction of psophometric current throughout the dc line length; the effectiveness of the higher harmonic component suppression of the passive filtering device in conjunction with active part is estimated. Special feature of harmonic component suppression in composite direct current line is noted.